Measurement of the Interfacial Stresses in Rolling Using the Elastic Deformation of the Roll

1987 ◽  
Vol 109 (4) ◽  
pp. 362-369 ◽  
Author(s):  
D. J. Meierhofer ◽  
K. A. Stelson
Keyword(s):  
Elastic Deformation ◽  
Normal Pressure ◽  
New Method ◽  
Frictional Stress ◽  
Stress Distributions ◽  
Strain Gages ◽  
Experimental Rolling ◽  
Mechanical Isolation ◽  
Roll Gap ◽  
Future Work

A new method to measure the frictional stresses and normal pressure in the roll gap during cold rolling, and experimental verification of this new method, are presented. The method overcomes many of the shortcomings of pin-type sensors. The elastic deformation of the roll itself is measured with strain gages, and is used to calculate the stresses between the sheet and the roll. Since no modification of the roll is necessary, the deformation process is undisturbed by the measurement. Mechanical isolation of the sensor is unnecessary. The mathematical procedure used to calculate the normal pressure and frictional stresses from the measured strains explicitly acknowledges that these strains are the result of the entire distribution of pressures and shears in the roll gap. An experimental rolling mill was constructed to verify the proposed method. Lead was rolled, and the resulting pressure and frictional stress distributions in the roll gap were measured. Several features of these distributions are in agreement with measurements made by various investigators using other techniques, thereby confirming the usefulness of the new method. Future work is proposed to increase the accuracy with which the roll gap stresses may be measured.

Effect of Thermal Distortion on Wear of Composites

1995 ◽  
Vol 117 (4) ◽  
pp. 622-628 ◽  
Author(s):  
Shingo Obara ◽  
Takahisa Kato
Keyword(s):  
Elastic Deformation ◽  
Composite Structure ◽  
Frictional Heating ◽  
Tetragonal Zirconia ◽  
Surface Profile ◽  
Normal Pressure ◽  
Oxide Ceramic ◽  
Thermal Distortion ◽  
Test Results ◽  
Worn Surface

The worn surface profile of a composite structure was experimentally and numerically investigated focusing on the effects of sliding conditions. Wear tests on composites made of an oxide ceramic and an amorphous metal against a tetragonal zirconia polycrystals-alumina were carried out under various mean contact pressures, P, and sliding velocities, V. The test results showed that the worn surface profiles of the composites changed with the PV value. A new numerical method for simulating the worn surface profile of a composite structure has been developed. The present method is based upon the assumption that the profile of a worn surface is changed by thermal distortion of the sliding bodies due to frictional heating and by elastic deformation due to normal pressure and friction traction. The calculated results were compared with the test results, and the comparison showed that the elastic deformation plays an important role in forming the worn surface profile and that the effect of thermal distortion becomes remarkable with an increase in PV values. The numerical results clarified the contribution of the thermal distortion to the change in the worn surface profile of the composite.

Effect of Steady Rest in Cylindrical Traverse Grinding of Slender Workpiece

2020 ◽  
Author(s):  
Hidetaka Fujii ◽  
Takashi Onishi ◽  
Chinhu Lin ◽  
Moriaki Sakakura ◽  
Kazuhito Ohashi
Keyword(s):  
Elastic Deformation ◽  
Contact Point ◽  
Traverse Speed ◽  
Grinding Force ◽  
New Method ◽  
Beam Model ◽  
Shape Error ◽  
Form Error ◽  
Low Stiffness ◽  
Traverse Grinding

Abstract In the case of traverse grinding of a slender workpiece, the ground workpiece is easily deformed by the normal grinding force due to its low stiffness. To reduce the form error caused by the elastic deformation of the workpiece, a steady rest is widely used. Generally, a steady rest is set to push the ground area of the workpiece. However, the stepped shape error is generated at the contact point where a steady rest pushed the workpiece because the pushing force of a steady rest is decreased after the material of the contact point is removed. In this study, to reduce the stepped shape error of the ground workpiece, we proposed a new method to set a steady rest. In this method, the steady rest was set to push the area where was not ground. In addition, the traverse speed of the workpiece was adjusted to keep the elastic deformation of the workpiece constant. The suitable method to control the traverse speed was estimated by using a beam model that could simulate the elastic deformation of the workpiece during the grinding process. It was confirmed that the new method could improve the form accuracy of a slender workpiece through grinding experiments.

Bounded Elastic Moduli Multiplier Technique for Limit Loads: Part 2 - Case Studies

2021 ◽  
Author(s):  
Sathya Prasad Mangalaramanan
Keyword(s):  
Lower Bound ◽  
Case Studies ◽  
Power Law ◽  
Elastic Moduli ◽  
New Method ◽  
Stress Distributions ◽  
Limit Loads ◽  
Elastic Plastic ◽  
Thick Cylinder ◽  
Better Than

Abstract An accompanying paper provides the theoretical underpinnings of a new method to determine statically admissible stress distributions in a structure, called Bounded elastic moduli multiplier technique (BEMMT). It has been shown that, for textbook cases such as thick cylinder, beam, etc., the proposed method offers statically admissible stress distributions better than the power law and closer to elastic-plastic solutions. This paper offers several examples to demonstrate the robustness of this method. Upper and lower bound limit loads are calculated using iterative elastic analyses using both power law and BEMMT. These results are compared with the ones obtained from elastic-plastic FEA. Consistently BEMMT has outperformed power law when it comes to estimating lower bound limit loads.

New strength metrics for containerboards: influences of basic papermaking factors

2018 ◽  
Vol 33 (4) ◽  
pp. 592-602
Author(s):  
Amanda Mattsson ◽  
Tetsu Uesaka
Keyword(s):  
Time Dependent ◽  
New Method ◽  
Creep Tests ◽  
Material Parameters ◽  
Dependent Failures ◽  
Short Term Strength ◽  
New Material ◽  
End Use ◽  
Future Work ◽  
Operating Window

Abstract In end-use, containerboard is subjected to a variety of loading histories, such as seconds of loading/unloading, hours of vibration, days of creep load. The fundamental question is whether the commonly measured static strength represents “strength” under these conditions. Another question is, since those time-dependent failures are notoriously variable, how to describe the probabilistic aspect. This study concerns the characterisation of these different facets of “strength”. In our earlier work, we have investigated the theoretical framework for time-dependent, probabilistic failures, and identified three material parameters: (1) characteristic strength, {S_{c}}, representing short-term strength, (2) brittleness/durability parameter, ρ, and (3) reliability parameter, β. We have also developed a new method that allows us to determine all these parameters much faster than typical creep tests. Using the new method, we have started investigating effects of basic papermaking variables on the new material parameters. Among the samples tested, the parameter ρ varied from 20 to 50, and β from 0.5 to 1.0. This suggests that, even within the current papermaking practice, there is a wide operating window to tune these new material parameters. The future work is, therefore, to find specific manufacturing variables that can systematically change these new material parameters.

Linear Static, Real-Time Finite Element Computations Based on Element Masks

2011 ◽  
Author(s):  
Holger Graf ◽  
Andre´ Stork
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Boundary Conditions ◽  
Real Time ◽  
Stiffness Matrix ◽  
New Method ◽  
Stress Distributions ◽  
Post Processing ◽  
Time Performance ◽  
Computational Overhead

This paper presents a new method for the manipulation of a given CAE domain in view of VR based explorations that enables engineers to interactively inspect and analyze a linear static domain. The interactions can ideally be performed in real-time in order to provide an intuitive impression of the changes to the underlying volumetric domain. We take the approach of element masking, i.e. the blending out of computations resulting from computational overhead for inner nodes, based on the inversion of the stiffness matrix. This allows us to optimize the re-simulation loop and to achieve real-time performance for strain and stress distributions with immediate visualization feedback caused by interactively changing boundary conditions. The novelty of the presented approach is a direct coupling of view dependent simulations and its close linkage to post-processing tasks. This allows engineers to also inspect the changes of the stress field inside of the volume during, e.g. cross sectioning.

Internal Stresses in Elastohydrodynamic Lubrication of Rolling/Sliding Contacts

1989 ◽  
Vol 111 (1) ◽  
pp. 180-187 ◽  
Author(s):  
Farshid Sadeghi ◽  
Ping C. Sui
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Internal Stress ◽  
Maximum Shear Stress ◽  
Elastohydrodynamic Lubrication ◽  
Normal Pressure ◽  
Internal Stresses ◽  
Stress Distributions ◽  
Principal Stresses ◽  
Dimensionless Velocity

The internal stress distribution in elastohydrodynamic lubrication of rolling/sliding line contact was obtained. The technique involves the full EHD solution and the use of Lagrangian quadrature to obtain the internal stress distributions in the x, y, z-directions and the shear stress distribution as a function of the normal pressure and the friction force. The principal stresses and the maximum shear stress were calculated for dimensionless loads ranging from (2.0452 × 10−5) to (1.3 × 10−4) and dimensionless velocity of 10−10 to 10−11 for slip ratios ranging from 0 to pure sliding condition.

Contact Stress for Toroidal Drive

2003 ◽  
Vol 125 (1) ◽  
pp. 165-168 ◽  
Author(s):  
Lizhong Xu ◽  
Zhen Huang ◽  
Yulin Yang
Keyword(s):  
Elastic Deformation ◽  
Contact Stress ◽  
Load Distribution ◽  
Contact Stresses ◽  
Periodic Change ◽  
Stress Distributions ◽  
Contact Strength ◽  
Optimal Parameters ◽  
Pair Number

Considering the elastic deformation of the rotor and the periodic change of the mesh teeth pair number, the calculation equations of the load distribution for the toroidal drive are presented. Based on the equations, the formulas for calculation of the contact stresses among stator and worm are introduced. By using the above-mentioned formulas, the contact stress distributions for the drive are obtained. The optimal parameters providing for equal contact strength of the stator and worm are determined. These results are useful in manufacture and design of the drive.

New Deployable Structures Based on an Elastic Origami Model

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Kazuya Saito ◽  
Akira Tsukahara ◽  
Yoji Okabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Simple Model ◽  
Elastic Deformation ◽  
Initial Strain ◽  
New Method ◽  
The Finite Element Method ◽  
Deployable Structures ◽  
Elastic Deformations ◽  
Plate Models

Traditionally, origami-based structures are designed on the premise of “rigid folding,” However, every act of folding and unfolding is accompanied by elastic deformations in real structures. This study focuses on these elastic deformations in order to expand origami into a new method of designing morphing structures. The authors start by proposing a simple model for evaluating elastic deformation in nonrigid origami structures. Next, these methods are applied to deployable plate models. Initial strain is introduced into the elastic parts as actuators for deployment. Finally, by using the finite element method (FEM), it is confirmed that the proposed system can accomplish the complete deployment in 3 × 3 Miura-or model.

A photoelastic examination of the stresses in rolls during rolling

1969 ◽  
Vol 4 (4) ◽  
pp. 245-260 ◽  
Author(s):  
F A Khayyat ◽  
P R Lancaster
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Contact Surface ◽  
Significant Variation ◽  
Normal Pressure ◽  
Neutral Point ◽  
Lateral Spread ◽  
Stress Distributions ◽  
Pure Lead ◽  
Roll Pressure

The paper describes some experiments to determine the stress distribution in rolls during the rolling of pure lead. The rolls were made from a hard transparent resin and the isochromatics and isoclinics were recorded whilst rolling was in progress. From these recordings the stress distributions were obtained. Particular reference was made to conditions of normal and shear stress at the contacting surfaces. The paper gives results for three roll diameters and for each of these four roll loads were applied. The experiments were carried out for both dry and lubricated conditions. The results of this work show a variation of the shear stress at the surface of contact accompanied by a change of sign at the neutral point. The normal roll-pressure curves are in general agreement with those found by workers using other techniques. The results also indicate a significant variation in the ratio (shear stress/normal pressure) over the contact surface, although this was decreased by lubrication. For a given roll load and diameter lubricated rolling, as opposed to dry rolling, increases the reduction but appears to have no effect on lateral spread. For a given roll load a decrease in roll diameter results in an increase in reduction, lateral spread, mean roll pressure, and friction.

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